You use PEMDAS or in some areas GEMDAS
Since there are no parenthesis set in place and no exponents we do (Multiplication or division first) whichever comes first. In this case it's division
7/7= 1 so your equation is now 7+(1)+7x7-7
Next you do multiplication which is 7*7 which is 49
7+(1)+49-7
Now you add or subtract whichever comes first
7+1 = 8
8+49-7
49+8 = 57
57-7 = 50
Your answer should be 50